A process to fabricate ultra-fine grain metal wire, comprising: inserting a plurality of metal strands into a flexible elastic polyurethane sheath having an accommodating slot for each of the strands of metal to form a sheathed strand assembly; equal channel angular pressing (ECAP pressing) the sheathed strand assembly through an ECAP die having a plurality of die channels corresponding to the plurality of metal strands. The process is designed to improve electric conductance and mechanical properties of elongated metal parts and is especially applicable to optimize the conductance and tensile strength of copper cables, wires, strings, and rods.